From: Jakub Kicinski <kuba@kernel.org>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com,
Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH net-next 0/5] net: skbuff: hide some bitfield members
Date: Fri, 14 Apr 2023 09:01:00 -0700 [thread overview]
Message-ID: <20230414160105.172125-1-kuba@kernel.org> (raw)
There is a number of protocol or subsystem specific fields
in struct sk_buff which are only accessed by one subsystem.
We can wrap them in ifdefs with minimal code impact.
This gives us a better chance to save a 2B and a 4B holes
resulting with the following savings (assuming a lucky
kernel config):
- /* size: 232, cachelines: 4, members: 28 */
- /* sum members: 227, holes: 1, sum holes: 4 */
- /* sum bitfield members: 8 bits (1 bytes) */
+ /* size: 224, cachelines: 4, members: 28 */
/* forced alignments: 2 */
- /* last cacheline: 40 bytes */
+ /* last cacheline: 32 bytes */
I think that the changes shouldn't be too controversial.
The only one I'm not 100% sure of is the SCTP one,
12 extra LoC for one bit.. But it did fit squarely
in the "this bit has only one user" category.
Jakub Kicinski (5):
net: skbuff: hide wifi_acked when CONFIG_WIRELESS not set
net: skbuff: hide csum_not_inet when CONFIG_IP_SCTP not set
net: skbuff: move alloc_cpu into a potential hole
net: skbuff: push nf_trace down the bitfield
net: skbuff: hide nf_trace and ipvs_property
include/linux/skbuff.h | 38 ++++++++++++++++++++++++++++++++++----
include/net/sock.h | 2 +-
net/core/dev.c | 3 +--
net/core/skbuff.c | 2 ++
net/sched/act_csum.c | 3 +--
net/socket.c | 2 ++
6 files changed, 41 insertions(+), 9 deletions(-)
--
2.39.2
next reply other threads:[~2023-04-14 16:04 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-14 16:01 Jakub Kicinski [this message]
2023-04-14 16:01 ` [PATCH net-next 1/5] net: skbuff: hide wifi_acked when CONFIG_WIRELESS not set Jakub Kicinski
2023-04-14 17:46 ` Florian Fainelli
2023-04-14 16:01 ` [PATCH net-next 2/5] net: skbuff: hide csum_not_inet when CONFIG_IP_SCTP " Jakub Kicinski
2023-04-14 17:47 ` Florian Fainelli
2023-04-14 16:01 ` [PATCH net-next 3/5] net: skbuff: move alloc_cpu into a potential hole Jakub Kicinski
2023-04-14 17:51 ` Florian Fainelli
2023-04-14 16:01 ` [PATCH net-next 4/5] net: skbuff: push nf_trace down the bitfield Jakub Kicinski
2023-04-14 17:50 ` Florian Fainelli
2023-04-14 21:06 ` Florian Westphal
2023-04-15 8:31 ` Pablo Neira Ayuso
2023-04-17 4:12 ` Jakub Kicinski
2023-04-14 16:01 ` [PATCH net-next 5/5] net: skbuff: hide nf_trace and ipvs_property Jakub Kicinski
2023-04-14 17:50 ` Florian Fainelli
2023-04-14 21:09 ` Florian Westphal
2023-04-14 22:07 ` Jakub Kicinski
2023-04-14 23:11 ` Florian Westphal
2023-04-15 0:44 ` Jakub Kicinski
2023-04-15 0:32 ` kernel test robot
2023-04-15 0:43 ` kernel test robot
2023-04-17 12:09 ` Simon Horman
2023-04-15 11:53 ` [PATCH net-next 0/5] net: skbuff: hide some bitfield members Eric Dumazet
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